Art of cracking hydrocarbon oils



ug. 19, 1930. E. c. HERTHEL ET A1.

ART oF CRACKING HYDROCARBON oILs Filed June 11, 1927 INVENTOR Eugene C. /crh Har'rj/ L. Pelzer BY ATTOKNEYS lzvatentved Aug. 19, 1930 "UNITED STATES PATENT OFFICE EUGENE C.-HER'IHEL, 0E CHICAGO, ILLINOIS, AND HARRY I.. PELZEE, or HIGHLAND, INDIANA, AssIGNons 'ro `sINcLAIR EEEINING COMPANY, oF NEW YORK, N. Y., A

CORPORATION OF MAINE AEI or cEAcxING HYDEoCAE'BoN oILs Application led :rune 11,-

This invention relates to improvements in the cracking lof heavier and higher boiling hydrocarbon oils, such as gas oil, for the production o lighter and lower boiling hydrocarbon oils, such as gasoline and gasoline- Containing distillates2 therefrom. More particularly, the inventlon relates to improvements in operations of the type described in application Serial No. 704,926, led April 8, 1924, which has matured into vPatent No. 1,634,666.

In the operation there described, a charge of oil in a pressure still is repeatedly circulated from a bulk supply drum through heating tubes and back to the bulk supply drum and a bed of fullersearth, or other absorbent or desulphurizing or filtering material, is maintained in the path of the circulating oil. In one capacity, this bed of fullers-I earth acts to remove from the circulating still charge asphaltic and pitch-like constituents,

particularly more objectionable constituents of thischaracter.

In carrying out this operation, we have observed a tendency, in many instances, toward the formation of an asphaltic or pitchy crust on top of the earthv bed. The formation of such a crust in turn tends to interf re with full effectiveness of the entire dept of the earth bed. The formation of such a crust in local spots or patches also tends to render thetearth bed ineiecve over local areas.

This invention provides` animproved operation in which any tendency toward formation of such a crust is inhibited, and in which any tendency of any such crust that may` form to interfere with full efectiveness of the entire bed of earth 'is reduced. The invention also provides for the addition of fresh earth tothe bed of earth maintained in the .still charge during operation.

In carrying/out the present invention, line' fullers earth is supplied to the Charge of oil circulating in the pressure still through the bed of earth therein in `suspension in raw oil supplied to the crackingA operation. The raw oil containing suspended fineI fullers earth may besupplied to the oil circulating from thebulk supply drum to the heating tubes after passage through the earth bed so that 1927. serial No. 198,251.

the suspended earth is caused to pass through .the heating tubes or it may be supplied to the circulatin still Charge just before it passes through t e earth bed. In either case, the fine fullers earth supplied in suspension in raw 011 is separated on the earth bed in the pressure still as the still charge circulates therethrough. Fresh earth may thus be added to the earth bed in the pressure still continuously durrectly introduced and from which the yad mixed retluxed condensate, unvaporized raw oil and sus ended fine earth are supplied to the circulatlng still charge.

The invention will be further described in connection with the accompanying drawings, which illustrate, in a conventional and diagrammatic manner, one form of apparatus adapted for the practice of the process of the invention; but it is intended and will be understoodthat-the invention is not limited to operations carried out in a specific form of apparatus used for purposes of illustration. In the accompanying drawings, Fig. 1 represents, in elevation and partly in section and with parts broken away, a pressure still system adapted for the practice of the process of the invention, Fig. 2 is a sectional culating oil from the bulk supply drum upwardly through the heatin tubes and back to the bulk supply drum. ing and lubricating the bearings of the circulating pump is supplied through connection 12. Ra'w'oil in excess of that required for cooling and lubricating the pump bearings may be supplied through this connection and forced into the oil circulatinl in the still through the ump bearings. onnection\13 is provide for pumping out the still at the end of a run and for initially charging the still at the beginning of a run. For tempering the heating gases passing through the heating lue in which the heating tubes 6 are arranged, a ortion of the heating gases2 escaping from t e heating flue may be recirculated through return flue 14, provided with suitable forcing means, for admixture with fresh hot products of combustion from the fire box 15.

Arranged in the bulk supply drum 5, below the normal liquid level. therein so as to be submerged in the still charge, is a bed 16 of fullers earthon a suitable supporting means 17 adapted to retain the fullers earth but to permit free passage of oil. This bed of fullers earth extends entirely across the bulk supply drum between the circulating connections 8 to the heating tubes and the circulating connections from the heatin tubes. This bed of earth is directly exposed to the circulating still charge, and due to its large area passage of the circulating' oil through the earth bed is relatively slow as compared to its rate of passage through the heating tubes.

Arranged above the bulk supply drum 5 is a reflux tower 18 connected to the bulk supply drum by a vapor line 19. Vapors remaining uncondensed escape from the upper end of the reflux tower 18 through vapor line 20 to the condenser 21 arranged to dis- ,charge into the receiver 22. The distillate product is discharged from this receiver through connection 23 and uncondensed vapors and gases through connection 24. 'Pressure in the system may be maintained and regulated by means of valve 25, or by suitable valves arranged beyond the condenser or receiver. Connection 26 is provided for introducing raw oil into the 'upper end of the reflux tower 18. Connection 27 is provided for discharging pitch-laden oil or tar from the circulating still charge during operation. y

The reflux condensate or oil mixture collecting in the lower end of the reiux tower 18 flows through connection 28 into the oil circulating from the bulkv supply drum 5 to the heating tubes 6 after passage through the earth bed 16 or'through connection 29 into the body of oil in the bulk supply drum 5 above the earth bed 16. The reflux condensate or oil mixture from the reflux tower ool oil for cool-` 18 may be directed either through connection 28 or through connection 29 or partly througlu` both` of these connections by appropriate valves as illustrated.

The support means 17 for the bed of fullers earth in the bulk supply drum 5 may consist of one or more screens of appropriate mesh to retain the fullers earth used arranged between perforated plates or gratings, as illustrated in Figs. 3 and 4.

-In operation, a bed of fuller-s earth is arranged in the still and the still then charged with oil and brought to cracking conditions of temperature and pressure in the usual way. In a still of the type illustrated in which the initial charge of oil amounts to about 8,000 gallons, the initial bed of fullers earth may consist 'of three or four tons of 1530 mesh fullers earth. For the production of gasoline from gas oil character chargingJK stock, for example, the still may be operated pnder a pressure inthe neighborhood of 125 pounds per square inch and the charge maintained at a corresponding cracking v temperature. vAfter the still is brought to cracking conditions of temperature and pressure, vapors are taken 0E through the reflux tower to the condenser andcondensed therein to form the distillate product and the introduction of raw oil is begun. Before the concentration of asphaltic and pitch-like constituents in the stillA charge reaches an objectionableA value, the discharge of pitch-laden oil from the still is begun. At 'this point in the operation, the distillate product may be taken oir" at a rate of about 1.000 gallons per hour, pitch-laden oil discharged at a rate of about 1.500 gallons per hour and raw oil supplied at a rate of about 2,500 gallons per hour. The refluxing operation is 'controlled to condense and reflux to the still components of the vapors heavier than desired as components of the distillate products by regulated introduction of raw o il into the vapors in the refluxing operation. Any raw oil supplied to the operation 1n excess of that introduced into the refluxing operation, in the pressure still illustrated, is forced in' through the bearings of the circulating pump. Such additional raw oil or part of it, however', may be supplied directly to the circulating still charge.

Fine fullers earth is supplied to the operation in suspension in the raw oil introduced into the reiuxing operation. Raw oil supplied directly to the circulating still charge.

may also' carry fineullers earth in suspension. The fine fullers earth so supplied to the operation in suspension in raw oil may, for example,'be of 60-100 mesh. It is advantageous to use relatively fine earth particularly where the-suspended earth is caused to circulate through the heating tubes of the still, but coarser earth may be used. The raw oil suspension may contain as much as onecarbon oils, which comprisesl circu ating ak 'in the path o Apar't of the line fullers earth may be discharged from the operation in suspension in discharged pitch-ladenoil.

Fullers earth is a particularly advanta# geous material to use in carrying out the present invention. Other similar absorbent earths and clays, however, are also useful in carrying out the invention. 1n lace of fullers earth, an initial bed of lterlng material such as pulverized coke or calcinedy bauxite may also be used in carrying out the invention.

We claim:

1. .An improved process of crackin hydrocharge of oil in a pressure still froma bulk supply drum through heating tubes and back to the bulk su ply drum, maintaining in the bulk suplply rum submer ed in the circulating c arge of oil therem and extending entirely across the bulk supply drum in the` path of thexzirculating oil a bed of finely divided fullers earth, heating the oil to a cracking temperature in the heatin tubes, taking off vapors from the bulk supp y drum under pressure, supplying raw oil to the charge of oil in the pressure still durin operation, and supplying linely divided tu lers earth to the operation in suspension in raw oil l so supplied to the still charge, whereby the tendency toward the formatlon of a pitchyV crust on top of theearth bed is inhibited.`

2. An improved process of cracking hydrocarbon oils, which comprises circulating a charge of oil in a pressure still from a bulk sup y drum through heating tubes and bac to the bulk supply drum, maintaining in the bulk supply drum submerged in the circulating charge of oil therein and extending entirey across the 4bulk su ply drum the circulatingoil) a bed of finely divided fullers earth, heating the oil to a, cracking temperature in the heating -V tubes, taking oii vapors .from the bulk supply drum under pressure, supplying raw oil to the circulating still charge as it circulates from the bulk supply drum to the heating tubes during operation, and supplying'inely divided fullers earth tothe cperation inf suspensionin raw oil so supplie to the still charge, whereby the tendency toward the formation of a pitchy crust on top of the earth bed is inhibited. j

' 3. An improved process of cracking hydrocarbon oils, which comprises circulating a charge of oil in a pressure still from a bulk supply drum through heating tubes and'back to the bulk supply drum, maintaining in the bulk supply drum submerged in the circulating charge of oil therein and extending entirely across the bulk supply drum in the `path of the circulating oil a bed Eof finely divided fullers earth, heatin the oil to a cracking temperature in the eating tubes, taking olf vapors from the bulk supply drum under pressure and subjecting them to a reluxing operation, intro ucing raw oil into direct contact with the vapors in this reflux'- ing operation, returning refiuxed condensate therefrom together with admixed unvaporized raw oil supplied thereto to the charge of oil in thev pressure still, and supplying finely divided fullers earth to the operation in suspension in raw oil so supplied to the still charge, whereby the tendency toward the formation of a pitchy crust on top of the earth'b-ed is inhibited.

4. y An improved process of cracking hydrocarbon oils, which comprises circulating a char e of oil in a pressure still from a'bulk supp y drum through heating tubes and back to the bulk supply drum, maintaining in the bulk supply drum submerged in the circulatling charge of oil therein and extending entirely across the bulk supply drum in the path of the circulating oil a bed 'of filtering material, heating the oil to a cracking temperature in the heating tubes, taking ofi' vapors from the bulk supply drum under pressure, supplying raw oil to the charge of oil in the pressure still during operation, and

supplyingQnely divided fullers earth to the operationin suspension in raw oil so supplied to the still charge, whereby the tendency toward the formation of a pitchy crust on top of the earth bed is'inhibited.

l 5. An improved process of cracking hydrocarbon oils, which comprises circulating a charge of oil in a pressure stillA froma bulk supp y drum through heating tubes and back lto the bulk supply drum, maintaining in the bulk supply drum submerged in the circulating charge of4 oil therein and extending entirely across the bulk supplyrdrum' in the` path of thecirculating oil a bed of finely dil Y vided solid absorbent material, heating the. f 

